Digital television transmitter/receiver and method of processing data in digital television transmitter/receiver

ABSTRACT

A digital television (DTV) transmitter and a method of processing data in the DTV transmitter/receiver are disclosed. In the DTV transmitter, a pre-processor pre-processes the enhanced data by coding the enhanced data for forward error correction (FEC) and expanding the FEC-coded data. A packet formatter generates one or more groups of enhanced data packets, each enhanced data packet including the pre-processed enhanced data and known data, wherein the data formatter adds burst time information into each group of enhanced data packets. And, a packet multiplexer generates at least one burst of enhanced data by multiplexing the one or more groups of enhanced data packets with at least one main data packet including the main data, each burst of enhanced data including at least one group of enhanced data packets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/456,785 filed on Jul. 11, 2006, now U.S. Pat. No. 7,756,011, whichclaims the benefit of the Korean Patent Application No. 10-2005-0113464,filed on Nov. 25, 2005, the contents of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital communication system, andmore particularly, to a digital television (DTV) transmitter/receiverand a method of processing data in the DTV transmitter/receiver.Although the present invention is suitable for a wide scope ofapplications, it is particularly suitable for transmitting and receivingdigital broadcasts.

2. Discussion of the Related Art

Generally, the 8T-VSB transmission system adopted as a digitalbroadcasting standard by Korea and North America is a digital broadcastsystem developed for MPEG video/audio data transmission.

As the digital signal processing technology rapidly develops with theglobal use of Internet, the tendency for combining digital homeappliances, computer and Internet together rises. So, in order to meetthe user's various demands, many efforts need to be made to develop asystem capable of transmitting various supplemental data withvideo/audio data.

A user of supplemental data broadcasting is expected to use thesupplemental data broadcasting using a PC card or portable device havinga simple type indoor antenna attached thereto.

Yet, signal intensity can be considerably decreased due to a shieldeffect of a wall and an influence of a near moving object within anindoor space and broadcast receiving performance can be reduced due to aghost and noise generated from a reflective wave. Unlike a case ofgeneral video/audio data, a case of supplemental data transmissionshould have a lower error rate. In case of the video/audio data, anerror failing to be detected by human eyes/ears does not matter. Yet, incase of supplemental data (e.g., a program execution file, stockinformation, etc.), a 1-bit error can cause a serious problem. So, thedemand for developing a system more persistent against ghost and noisegenerated from a channel rises.

Additional data transmission will be performed by time-division throughthe same channel of MPEG video/audio in general. Since the beginning ofdigital broadcasting, ATSC VSB digital broadcast receivers receiving theMPEG video/audio only have globally spread in markets. So, thesupplemental data transmitted on the same channel of the MPEGvideo/audio should avoid causing any effect to the conventional ATSC VSBdedicated receiver previously supplied to the markets. Such a situationis defined as ATSC VSB compatibility. And, a supplemental data broadcastsystem should be compatible with the ATSC VSB system. Besides, thesupplemental data could be called enhanced data or E-VSB data.

However, in a poor channel environment, reception performance of theconventional ATSC VSB reception system may be reduced. Specifically, aportable or mobile receiver needs higher robustness against a channelchange and noise.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a digital television(DTV) transmitter and a method of coding main and enhanced data in theDTV transmitter that substantially obviate one or more problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a digital television(DTV) transmitter and a method of coding main and enhanced data in theDTV transmitter, by which a new digital broadcast system suitable forsupplemental data transmission and robust against noise can be provided.

Another object of the present invention is to provide a digitaltelevision (DTV) transmitter and a method of coding main and enhanceddata in the DTV transmitter, by which reception performance can beenhanced by transmitting data known by a transmitting/receiving side ina manner of inserting the known data in a prescribed area of a datasection.

A further object of the present invention is to provide a digitaltelevision (DTV) transmitter and a method of coding main and enhanceddata in the DTV transmitter, by which various transmission parametersfor a transmitted signal can be efficiently transmitted and received.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adigital television (DTV) transmitter for coding main and enhanced dataincludes a pre-processor for pre-processing the enhanced data by codingthe enhanced data for forward error correction (FEC) and expanding theFEC-coded data, a packet formatter for generating one or more groups ofenhanced data packets, each enhanced data packet including thepre-processed enhanced data and known data, wherein the data formatteradds burst time information into each group of enhanced data packets,and a packet multiplexer for generating at least one burst of enhanceddata by multiplexing the one or more groups of enhanced data packetswith at least one main data packet including the main data, each burstof enhanced data including at least one group of enhanced data packets.

Herein, the burst time information may indicate a time representing atotal length of a current burst of enhanced data. The burst timeinformation may indicate a time between each group of enhanced datapackets included in a current burst of enhanced data and a next burst ofenhanced data. The burst time information may also indicate a locationof each group of enhanced data packets within a burst of enhanced data.And, the burst time information may further indicate a time between acurrent group of enhanced data packets and a next group of enhanced datapackets within a burst of enhanced data. In addition, the data formattermay further add specific information associated with the known data intoeach group of enhanced data packets.

In another aspect of the present invention, a method of coding main andenhanced data in a digital television (DTV) transmitter includespre-processing the enhanced data by coding the enhanced data for forwarderror correction (FEC) and expanding the FEC-coded data, generating oneor more groups of enhanced data packets, each enhanced data packetincluding the pre-processed enhanced data and known data, generating atleast one burst of enhanced data by multiplexing the one or more groupsof enhanced data packets with at least one main data packet includingthe main data, each burst of enhanced data including at least one groupof enhanced data packets, and adding burst time information into eachgroup of enhanced data packets.

Herein, the burst time information may indicate a time representing atotal length of a current burst of enhanced data. The burst timeinformation may indicate a time between each group of enhanced datapackets included in a current burst of enhanced data and a next burst ofenhanced data. The burst time information may also indicate a locationof each group of enhanced data packets within a burst of enhanced data.And, the burst time information may further indicate a time between acurrent group of enhanced data packets and a next group of enhanced datapackets within a burst of enhanced data.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a block diagram of a digital broadcast transmitting systemaccording to one embodiment of the present invention;

FIG. 2 is a block diagram of a digital broadcast transmitting systemaccording to another embodiment of the present invention;

FIG. 3 is a detailed block diagram of a frame multiplexer according toone embodiment of the present invention to transmit a transmissionparameter by inserting the transmission parameter in a field syncsegment;

FIG. 4 is a detailed block diagram of an E-VSB packet formatteraccording to one embodiment of the present invention to transmit atransmission parameter by inserting the transmission parameter in agroup;

FIG. 5 is a detailed block diagram of a convolutional coder of thetransmitting system shown in FIG. 1 according to one embodiment of thepresent invention to transmit a transmission parameter by multiplexingthe transmission parameter in a symbol domain; and

FIG. 6 is a detailed block diagram of a part relating to an E-VSB symbolprocessor of the transmitting system shown in FIG. 2 according to oneembodiment of the present invention to transmit a transmission parameterby multiplexing the transmission parameter in a symbol domain.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

In the present invention, enhanced data can correspond to such datahaving information such as a program execution file, stock informationand the like or may correspond to video/audio data. And, known data isthe data previously known by agreement between transmitting andreceiving sides. Moreover, main data is the data receivable by aconventional receiving system and includes video/audio data.

In transmitting a signal in a manner of inserting the known data alreadyknown by both of the transmitting and receiving sides in a prescribedposition within an enhanced data packet, the present invention is totransmit or receive various transmission parameters associated with thetransmission signal.

In particular, there exist various parameters for a signal transmittedby the E-VSB transmitting system and a receiving system has to know thetransmission parameters of the transmitted signal to correctly receivethe corresponding signal. For instance, information indicating how datain a symbol domain are processed by an E-VSB symbol processor totransmit an E-VSB signal is needed. And, information indicating howmultiplexing is performed between main data and enhanced data or betweenvarious kinds of enhanced data. Moreover, information for a separategroup, information for a burst and the like are needed as transmissionparameters to transmit enhanced data packets configured with at leastone of enhanced data and known data by burst unit in a manner ofgrouping the enhanced data packets.

The present applicant has filed a patent application for a transmittingmethod of grouping enhanced data packets including at least one ofenhanced data and known data.

FIG. 1 is a block diagram of a digital broadcast transmitting systemaccording to one embodiment of the present invention, and FIG. 2 is ablock diagram of a digital broadcast transmitting system according toanother embodiment of the present invention.

Referring to FIG. 1, a digital broadcast transmitting system accordingto one embodiment of the present invention includes an E-VSBpre-processor 101, an E-VES packet formatter 102, a packet multiplexer103, a data randomizer 104, a scheduler 105, an E-VSB post-processor110, an RS (Read-Solomon) encoder 121, a data interleaver 122, a trellisencoder 123, a backward-compatibility processor 124, a frame multiplexer125 and a transmitter 130.

In the above-configured transmitting system, main data is outputted tothe packet multiplexer 103 by transport packet unit, whereas enhanceddata is outputted to the E-VSB pre-processor 101.

The E-VSB pre-processor 101 performs pre-processing such as additionalerror correction encoding, interleaving, null data insertion and thelike on the enhanced data and then outputs the pre-processed data to theE-VSB packet formatter 102.

The E-VSB packet formatter 102 configures a group by multiplexing thepre-processed enhanced data and previously defined known data togetherunder the control of the scheduler 105. The E-VSB packet formatter 102divides data within the group into 184-byte enhanced data packets,attaches a 4-byte MPEG header to a front of each of the packets and thenoutputs a 186-byte enhanced data packet (i.e., MPEG compatible packet).In particular, one enhanced data packet group includes a plurality ofconsecutive enhanced data packets.

An output of the E-VSB packet formatter 102 is inputted to the packetmultiplexer 103. The packet multiplexer 103 performs time divisionmultiplexing on the main data packet and the enhanced data packet bytransport stream (TS) packet unit to output under the control of thescheduler 105.

In particular, the scheduler 105 generates a control signal enabling thepacket multiplexer 103 to multiplex the main and enhanced data packetstogether and then outputs the control signal to the packet multiplexer103. If so, the packet multiplexer 103 having received the controlsignal multiplexes the main data packet and the enhanced data packetinto the TS packet unit to output.

An output of the packet multiplexer 103 is outputted to the datarandomizer 104. The data randomizer 104 removes MPEG sync byte from aninput packet, randomizes the rest 187 bytes using an internallygenerated pseudo-random byte and then outputs the randomized packet tothe E-VSB post-processor 110.

The E-VSB post processor 110 includes an RS encoder 111, a datainterleaver 112, a convolutional coder 113, a data deinterleaver 114 andan RS byte remover 115. Data processed by the E-VSB post-processor 110is outputted to the frame multiplexer 125 via the RS encoder 121, thedata interleaver 122 and the trellis encoder 123. In this case, theconvolutional coder 113 includes a byte-to-symbol converter, an E-VSBsymbol processor and a symbol-to-byte converter.

In order to make output data of the trellis encoder 123 into the knowndata defined by a transmitting/receiving side, initialization of amemory within the trellis encoder 123 is needed for the known datainserted in the enhanced packet. In doing so, since the initializationis achieved not by input data but by new data, RS parity should bere-generated to replace original parity data. This is performed by thecompatibility processor 124.

The frame multiplexer 125 configures 832-symbol data segment byinserting four segment sync symbols in each 828 symbols of outputsymbols of the trellis encoder 123 and configures one data fieldconsisting of total 313 segments by inserting one field sync segment ineach 312 data segments. The frame multiplexer 125 then outputs theconfigured data field to the transmitter 130.

FIG. 2 is a block diagram of a digital broadcast transmitting systemaccording to another embodiment of the present invention.

Referring to FIG. 2, a digital broadcast transmitting system accordingto another embodiment of the present invention includes an E-VSBpre-processor 201, an E-VSB packet formatter 202, a packet multiplexer203, a data randomizer 204, a scheduler 205, an RS encoder & parityplace holder inserter 206, a data interleaver 207, a byte-to-symbolconverter 208, an E-VSB symbol processor 209, a known data generator210, a symbol-to-byte converter 211, a non-symmetric RS encoder 212, atrellis encoder 213, a frame multiplexer 314 and a transmitter 220.

The E-VSB packet formatter 202 shown in FIG. 2 configures a group in amanner of determining a known data place holder, in which known datawill be inserted within a packet, inserting null data in the determinedknown data place holder, and multiplexing it with output data of theE-VSB pre-processor 201. The E-VSB packet formatter 202 divides datawithin the group into 184-byte enhanced data packets and attaches a4-byte MPEG header to a front of each of the packets to output a188-byte enhanced data packet (i.e., MPEG compatible packet). So, aplurality of enhanced data packets are consecutively included in oneenhanced data packet group.

An output of the E-VSB packet formatter 202 is inputted to the packetmultiplexer 203. The packet multiplexer 203 performs time divisionmultiplexing on the main data packet and the enhanced data packet intotransport stream (TS) packet unit under the control of the scheduler205.

An output of the packet multiplexer 203 is outputted to the datarandomize 204. The data randomizer 204 removes MPEG sync byte from aninput packet, randomizes the rest 187 bytes using an internallygenerated pseudo-random byte and then outputs the randomized packet tothe Reed-Solomon (RS) encoder & parity place holder inserter 205.

The Reed-Solomon (RS) encoder & parity place holder inserter 206performs systematic RS encoding or non-systematic RS parity holderinsertion on the randomized data. An output of the Reed-Solomon (RS)encoder & parity place holder inserter 206 is inputted to the framemultiplexer 214 via the data interleaver 207, the byte-to-symbolconverter 208, the E-VSB symbol processor 209 and the trellis encoder213.

The frame multiplexer 214 configures 832-symbol data segment byinserting four segment sync symbols in each 828 symbols of outputsymbols of the trellis encoder 213 and configures one data fieldconsisting of total 313 segments by inserting one field sync segment ineach 312 data segments. The frame multiplexer 214 then outputs theconfigured data field to the transmitter 220.

A transmission parameter in the above-configured E-VSB transmittingsystem shown in FIG. 1 or FIG. 2 can be transmitted by being inserted invarious places using various methods.

According to a first embodiment of the present invention, thetransmission parameter can be inserted in a manner of allocating aportion of a reserved area within a field sync segment of a VSB frame.In this case, a receiving system is able to detect the transmissionparameter before decoding of a received signal is performed in a symboldomain. So, a transmission parameter having information for a processingmethod of the E-VSB symbol processor can be inserted in the reservedarea of the field sync signal. In particular, the receiving system isable to detect the transmission parameter from an agreed place afterobtaining field synchronization using the field sync segment.

According to a second embodiment of the present invention, the E-VSBpacket formatter is able to insert a transmission parameter by assigninga specific area as an area for the transmission parameter within a unitof group. In this case, in a receiving system, after synchronization andequalization are performed on a received signal and channel decoding (orerror correction decoding) in the symbol domain is performed. An E-VSBpacket de-formatter then separates enhanced data and transmissionparameter to detect.

According to a third embodiment of the present invention, thetransmission parameter can be multiplexed with other data symbols in asymbol domain. For instance, in multiplexing known data symbol and mainor enhanced data symbol together to output to an E-VSB symbol processor,a transmission parameter symbol can be multiplexed instead of a knowndata symbol to be inserted in a place in which the known data symbol canbe inserted.

According to a fourth embodiment of the present invention, it is able totransmit the transmission parameter by inserting the transmissionparameter in a layer higher than that of a transport stream packet. Inthis case, a receiving system should be able to receive and decode thetransmitted signal into a equal to or higher than the TS packet layer.For this, the transmission parameter plays a role as verification for atransmission parameter of a currently received signal and a role ingiving a transmission parameter of a signal to be received later.

In the present invention, various transmission parameters for atransmission signal are transmitted by being inserted by the aforesaidmethods according to the embodiments of the present invention. In thiscase, the transmission parameters can be inserted to be transmittedaccording to one of the embodiments only, a portion of the embodimentsor the entire embodiments. And, information within the transmissionparameter can be overlapped to be inserted in each of the embodiments ornecessary information can be inserted in a corresponding place to betransmitted according to the corresponding embodiment.

In case that information for a processing method of the E-VSB symbolprocessor shown in FIG. 1 or FIG. 2 is transmitted as a portion of atransmission parameter, a receiving system is able to perform decodingcorresponding to the E-VSB symbol processor only if knowing theinformation for the symbol processing method. So, the information forthe processing method of the E-VSB symbol processor should be knownprior to the symbol-domain decoding.

In this case, it is able to transmit a transmission parameter havinginformation for the processing method of the E-VSB symbol processoraccording to the first embodiment by inserting the transmissionparameter in a reserved area of the field sync signal. This is becausethe transmission parameter can be detected before the symbol-domaindecoding for a received signal is performed in a receiving system.

It is able to transmit the transmission parameter by inserting thetransmission parameter having information for the processing method ofthe E-VSB symbol processor according to the third embodiment. In thiscase, since a symbol processing method for a transmission parametersymbol itself and a place of the transmission parameter symbol aredetermined in advance, the transmission symbol parameter should beplaced to be transmitted/received in advance of other data to bedecoded. If so, a receiving system is able to use the transmissionparameter symbol for the decoding of the data symbol by detecting thetransmission parameter symbol prior to the data symbol decoding.

Meanwhile, in case that information for the processing method of theE-VSB symbol processor in a transmission parameter inserted in a layerequal to or higher than a TS packet layer and a transmission parameterinserted by the E-VSB packet formatter according to the second or fourthembodiment, detection is possible after completion of decoding in asymbol domain. So, it is unable to use the information for currentsymbol decoding. Instead, the information can be used in confirminginformation for a processing method of a current E-VSB symbol processoror as information for a processing method of the E-VSB symbol processorof a next group or burst.

The first to fourth embodiments of the present invention are explainedin detail with reference to the attached drawings as follows.

First Embodiment Case of Inserting Transmission Parameter in Field SyncSegment Area

FIG. 3 is a detailed block diagram of the frame multiplexer (125 or 214)shown in FIG. 1 or FIG. 2 according to one embodiment of the presentinvention to transmit a transmission parameter by inserting thetransmission parameter in a field sync segment.

Referring to FIG. 3, the frame multiplexer includes a first multiplexer301 multiplexing a field sync signal and a transmission parameter and asecond multiplexer 302 multiplexing an E-VSB data symbol, a segment syncsignal and an output of the first multiplexer 301 to output.

A VSB frame generally consists of two fields and each of the fieldsconsists of one field sync segment and 312 data segments. Each of thedata segments consists of total 832 symbols. In this case, first foursymbols of one data segment corresponds a segment sync part and a firstsegment of one field corresponds to a field sync part.

One field sync signal consists of one segment length. A data segmentsync pattern exists in first four symbols, a pseudo-random sequence ofPN 511, PN 63, PN 63 and PN 63 exists next to the data segment syncpattern, and VSB mode associated information exists in the next 24symbols. The rest 104 symbols next to the 24 symbols of the VSB modeassociated information are reserved. Last 12 symbol data of a previoussegment are copied into last 12 symbols of the reserved area. If so, 92symbols of the field sync segment practically become a reserved area.

The first multiplexer 301 multiplexes the transmission parameter with afield sync segment symbol to insert the transmission parameter to beinserted in the reserved area of the field sync segment and then outputsthe multiplexed signal to the second multiplexer 302.

The second multiplexer 302 configures a new VSB frame by multiplexing asegment sync symbol, data symbols and a new field sync segment outputtedfrom the first multiplexer 301 together. A transmission frame includingthe field sync segment having the E-VSB transmission parameter insertedtherein is inputted to a transmitter.

In this case, the reserved area within the field sync segment forinserting the transmission parameter can be a portion or whole part ofthe reserved area of the 92 symbols or a portion or whole part of anarea except 64 symbols used for an enhanced mode map among the 92-symbolreserved area.

The transmission parameter inserted in the reserved area can includeinformation for discriminating a signal of a general 8-VSB transmissionmode, a signal of an enhanced VSB transmission mode or a signal ofanother kind of enhanced VSB transmission mode for example.

Second Embodiment Case of Inserting Transmission Parameter in E-VSBPacket Formatter

FIG. 4 is a detailed block diagram of the E-VSB packet formatter (102,202) shown in FIG. 1 or FIG. 2 according to one embodiment of thepresent invention to transmit a transmission parameter by inserting thetransmission parameter in a group.

Referring to FIG. 4, the E-VSB packet formatter includes an enhanceddata formatter 401, a know data generator 402, a transmission parametergenerator 403, a multiplexer 404 and an MPEG TS packetizer 405.

If enhanced data is inputted from the E-VSB pre-processor, the enhanceddata formatter 401 aligns the enhanced data within a group and thenoutputs the aligned data to the multiplexer 404.

And, the known data generator 402 generates known data and then outputsthe generated data to the multiplexer 404 as well.

If the E-VSB packet formatter is applied to FIG. 1, the known datagenerator 402 is able to practical known data or a known data placeholder. If the E-VSB packet formatter is applied to FIG. 2, the knowndata generator 402 is able to output a known data place holder in whichnull data is inserted.

And, the transmission parameter generator 403 generates a transmissionparameter associated with a group or burst and then outputs thegenerated parameter to the multiplexer 404. In particular, thetransmission parameter can include information for a length of a currentburst, information indicating a timing point of a next burst, a placeand length where groups exists within burst, a time to a next group froma current group within burst, information for known data and the like.

The multiplexer 404 configures a group by multiplexing the enhanced dataoutputted from the enhanced data formatter 401, the known data (or knowndata place holder) outputted from the known data generator 402 and thetransmission parameter outputted from the transmission parametergenerator 403 together.

An output of the multiplexer 404 is inputted to the MPEG TS packetizer405.

The MPEG TS packetizer 405 divides data within a group into 184-byteenhanced data packets, attaches a 4-byte MPEG header to a front of eachof the packets and then outputs a 188-byte enhanced data packet (i.e.,MPEG TS compatible packet).

In this case, an E-VSB packet de-formatter of a receiving system canseparate to detect the transmission parameters and enhanced data fromeach other.

Third Embodiment Case of Inserting Transmission Parameter in SymbolDomain

FIG. 5 is a detailed block diagram of the convolutional coder (113) ofthe transmitting system shown in FIG. 1 according to one embodiment ofthe present invention to transmit a transmission parameter bymultiplexing the transmission parameter with a data symbol and knowndata in a symbol domain.

Referring to FIG. 5, the convolutional coder includes a byte-to-symbolconverter or 12-way interleaver 501, a known data generator 502, atransmission data generator 503, a first multiplexer 504, a secondmultiplexer 505, an E-VSB symbol processor 506 and a symbol-to-byteconverter or 12-way deinterleaver 507.

In this case, the E-VSB packet formatter shown in FIG. 1 determines aknown data place holder in which known data will be inserted, insertsnull data in the determined data place holder and then multiplexes itwith enhanced data pre-processed by the E-VSB pre-processor, forexample.

The byte-to-symbol converter 501 converts an output byte of the datainterleaver to a symbol to output. In this case, the data byte outputtedfrom the data interleaver corresponds to one of main data, enhanced dataand known data (or known data place holder). One byte is converted tofour symbols. And, each of the symbols consists of two bits.

Each of the symbols is able to have an attribute indicating whether itssymbol corresponds to the main data, the enhanced data or the known dataplace holder.

In FIG. 5, a solid line indicates a data flow and a dotted lineindicates an attribute of each data. In particular, ‘M’ indicates a maindata attribute, ‘E’ indicates an enhanced data attribute and ‘T’indicates a known data attribute.

The known data generator 502 simultaneously outputs a known data symboland known data attribute information indicating the known data.

The transmission parameter generator 503 simultaneously outputs atransmission parameter symbol and its attribute information. In thiscase, the attribute information can be outputted as an attribute of theknown or enhanced data.

The first multiplexer 504 multiplexes the known data symbol outputtedfrom the known data generator 502 and the transmission parameter symboloutputted from the transmission parameter generator 503 together andthen outputs the multiplexed symbol to the second multiplexer 505together with the corresponding attribute information.

The second multiplexer 505 selects an output symbol of thebyte-to-symbol converter 501 or an output symbol of the firstmultiplexer 504 according to an attribute of the symbol outputted fromthe byte-to-symbol converter 501 and then outputs the selected symbol tothe E-VSB symbol processor 506 together with its attribute information.

In particular, if the attribute of the symbol outputted from thebyte-to-symbol converter 501 corresponds to the main or enhanced dataattribute, the second multiplexer 505 selects the symbol outputted fromthe byte-to-symbol converter 501 and the attribute information of thecorresponding symbol and then outputs them to the E-VSB symbol processor506. If the attribute of the symbol outputted from the byte-to-symbolconverter 501 is the attribute of the known data (or known data placeholder), the second multiplexer 505 selects the symbol outputted fromthe first multiplexer 504 and the attribute information of thecorresponding symbol and then outputs them to the E-VSB symbol processor506.

Hence, if the data symbol outputted from the second multiplexer 505 isthe main data symbol, the symbol has the attribute of main data. If thedata symbol outputted from the second multiplexer 505 is the enhanceddata symbol, the symbol has the attribute of enhanced data. Yet, in caseof the transmission parameter symbol, the symbol can have the symbolattribute outputted from the transmission parameter generator 503, i.e.,the attribute of the known or enhanced data.

The E-VSB symbol processor 506 performs a symbol processing process onthe symbol having the attribute of enhanced data. For instance,additional encoding of ½ coding rate can be performed on the symbolhaving the attribute of enhanced data.

The E-VSB symbol processor 506 does not perform additional encoding onthe symbol having the attribute of main or known data.

Even if the MPEG header byte inserted in the enhanced data packet by theE-VSB packet formatter or the RS parity byte attached to the enhanceddata packet by the RS encoder is converted to a symbol, the E-VSB symbolprocessor 506 outputs the symbol like the main data without changing thedata. This is because the symbol has the attribute of main data.

In case that the transmission parameter symbol has the attribute ofknown data, the E-VSB symbol processor 506 processes to output thecorresponding symbol in the same manner of the known data. In case thatthe transmission parameter symbol has the attribute of enhanced data,the E-VSB symbol processor 506 is able to process to output thecorresponding symbol in the same manner of the enhanced data. Inparticular, the transmission parameter symbol having the attribute ofknown data does not go through additional encoding and the transmissionparameter symbol having the attribute of enhanced data can go throughadditional encoding at ½ coding rate.

In other words, if the transmission parameter symbol has the attributeof known data, it is processed via the same path of the known data bythe E-VSB symbol processor 506. So, additional encoding is not performedin the symbol domain for the transmission parameter symbol. But,additional encoding is performed in the symbol domain if thetransmission parameter symbol has the attribute of enhanced data.

An output symbol of the E-VSB symbol processor 506 is converted to abyte by the symbol-to-byte converter 507 and is then outputted to thedata de-interleaver. The byte-to-symbol converter 501 is identical to abyte-to-symbol converter of the trellis encoder. And, the symbol-to-byteconverter 507 has a process reverse to that of the byte-to-symbolconverter.

FIG. 6 is a detailed block diagram of a part relating to an E-VSB symbolprocessor of the transmitting system shown in FIG. 2 according to oneembodiment of the present invention to transmit a transmission parameterby multiplexing the transmission parameter in a symbol area.

Referring to FIG. 2, a part relating to an E-VSB symbol processor of thetransmitting system shown in FIG. 2 according to one embodiment of thepresent invention includes a known data generator 601, a transmissionparameter generator 602, a first multiplexer 603, a second multiplexer604 and an E-VSB symbol processor 605.

The known data generator 601 has the same block of the known datagenerator 210 shown in FIG. 2.

Each of the symbols outputted from the byte-to-symbol converter is ableto have an attribute indicating whether its symbol corresponds to themain data, the enhanced data or the known data place holder.

In FIG. 6, a solid line indicates a data flow and a dotted lineindicates an attribute of each data. In particular, ‘M’ indicates a maindata attribute, ‘E’ indicates an enhanced data attribute and ‘T’indicates a known data attribute.

The known data generator 601 simultaneously outputs a known data symboland known data attribute information indicating the known data.

The transmission parameter generator 602 simultaneously outputs atransmission parameter symbol and its attribute information. In thiscase, the attribute information can be outputted as an attribute of theknown or enhanced data.

The first multiplexer 603 multiplexes the known data symbol outputtedfrom the known data generator 601 and the transmission parameter symboloutputted from the transmission parameter generator 602 together andthen outputs the multiplexed symbol to the second multiplexer 604together with the corresponding attribute information.

The second multiplexer 604 selects an output symbol of thebyte-to-symbol converter or an output symbol of the first multiplexer603 according to an attribute of the symbol outputted from thebyte-to-symbol converter and then outputs the selected symbol to theE-VSB symbol processor 605 together with its attribute information.

In particular, if the attribute of the symbol outputted from thebyte-to-symbol converter corresponds to the main or enhanced dataattribute, the second multiplexer 604 selects the symbol outputted fromthe byte-to-symbol converter and the attribute information of thecorresponding symbol and then outputs them to the E-VSB symbol processor605. If the attribute of the symbol outputted from the byte-to-symbolconverter is the attribute of the known data (or known data placeholder), the second multiplexer 604 selects the symbol outputted fromthe first multiplexer 603 and the attribute information of thecorresponding symbol and then outputs them to the E-VSB symbol processor605.

The E-VSB symbol processor 605 performs additional encoding of ½ codingrate on the inputted symbol having the attribute of enhanced data. TheE-VSB symbol processor 605 does not perform additional encoding on theinputted symbol having the attribute of main or known data.

Even if the MPEG header byte inserted in the enhanced data packet by theE-VSB packet formatter or the RS parity byte attached to the enhanceddata packet by the RS encoder is converted to a symbol, the E-VSB symbolprocessor 605 outputs the symbol like the main data without changing thedata.

In case that the transmission parameter symbol has the attribute ofknown data, additional encoding is not performed like the known data. Incase that the transmission parameter symbol has the attribute ofenhanced data, additional encoding is performed at ½ coding rate likethe enhanced data.

And, the E-VSB symbol processor 605 generates to output a data symbolenabling a memory of a trellis encoder to be reset to a predeterminedvalue at a portion where a sequence of known data symbols starts. Forthis, a memory value in the trellis encoder is inputted to the E-VSBsymbol processor 605.

The trellis encoder is reset when the sequence of the known data starts.This is because various output sequences are possible according to thememory state of the trellis encoder even if the known data sequence isinputted to the trellis encoder.

Hence, after the memory state of the trellis encoder has been reset tothe predetermined value, if the known data is inputted, it is able toobtain the known data sequence from an output of the trellis encoder aswell.

An output symbol of the E-VSB symbol processor 605 is outputted to thetrellis encoder and the symbol-to-byte converter.

Thus, in the present invention, a transmission parameter can betransmitted by being inserted in a reserved area of a field sync segmentof a VSB frame and/or a predetermined place of a group.

And, the transmission parameter can be transmitted by being multiplexedwith other data symbols in a symbol domain.

Moreover, the transmission parameter can be transmitted by beinginserted in a layer higher than a transport stream packet.

Accordingly, the present invention provides the following effects oradvantages.

First of all, the present invention is strong against error intransmitting supplemental data via a channel. And, the present inventionis compatible with a conventional VSB receiver. Moreover, the presentinvention enables an errorless reception of supplemental data on achannel having ghost and noise worse than those of the related art VSBsystem.

Secondly, the present invention transmits known data inserted in aspecific place of a data area, thereby enhancing reception performanceof a receiving system having considerable channel variations.

In particular, the present invention transmits transmission parametersassociated with a transmission signal by various places and methods,thereby being applicable to data demodulation and decoding in a mannerof extracting the transmission parameters efficiently in a receivingsystem.

Finally, the present invention is effectively applicable to a portableor mobile receiver requiring robustness against noise with considerablechannel variations.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A broadcasting transmitter for processing a digital television (DTV)broadcasting signal, the broadcasting transmitter comprising: arandomizer for randomizing enhanced data; a convolutional encoder forconvolutional encoding the randomized enhanced data: a deinterleaver fordeinterleaving the convolutional encoded enhanced data and known data; aReed-Solomon (RS) encoder for RS-encoding the deinterleaved data; aninterleaver for interleaving the RS-encoded data, wherein theinterleaved data further include main data, and wherein a convolutionencoding process was not performed on the main data; and a trellisencoder, having at least one memory, for trellis-encoding theinterleaved data, wherein the trellis encoder initializes the at leastone memory at a position where the known data starts.
 2. A method forprocessing a digital television (DTV) broadcasting signal in abroadcasting transmitter, the method comprising: randomizing enhanceddata; convolutional encoding the randomized enhanced data;deinterleaving the convolutional encoded enhanced data and known data;RS-encoding the deinterleaved data; interleaving the RS-encoded data,wherein the interleaved data further include main data, and wherein aconvolution encoding process was not performed on the main data; andtrellis-encoding the interleaved data in a trellis encoder having atleast one memory, wherein the trellis encoder initializes the at leastone memory at a position where the known data starts.